1. Field of the Invention
This invention relates to a printing method and apparatus for performing printing through a sequential method by scanning a plurality of printing heads, as well as to printed matter obtained by this printing method and a processed article obtained by working the printed matter.
2. Description of the Related Art
Conventional textile printing methods for printing on fabrics or textiles mainly are of two types, namely roller textile printing in which a pattern is engraved in a roller and the roller is pressed against a cloth to produce a continuous design, and screen textile printing in which a printing plate is fabricated into the shape of a screen and the number of screen plates used corresponds to the number of colors desired to be superimposed and the number of patterns desired to be overlapped. A printing apparatus which has been put into practical use as a substitute for these methods applies an ink-jet printing system to cloth.
A printer and a copying apparatus employing paper as the printing medium are known as printing apparatus that perform ink-jet printing. Such a printing apparatus jets a plurality of inks of the primary colors in the form of a dot matrix on the printing medium so that it is possible to express a diversity of colors by mixing colors, wherein the colors are mixed by arranging or superposing dots. This makes it possible to provide an entirely new design environment. Since the apparatus produces little noise, the effects upon the surroundings are reduced. In addition, the apparatus is capable of revolutionizing the manufacturing site. For these reasons, the aforementioned printing apparatus has become the focus of much attention.
However, certain problems arise when cloth is adopted as the printing medium. Specifically, the term xe2x80x9cclothxe2x80x9d includes not only natural fibers such as cotton, silk and fur but also synthetic fibers such as nylon, polyester and acrylic fiber. Various technical difficulties arise depending upon the type of printing medium, example of which are as mentioned.
In techniques for printing on cloth using the conventional ink-jet method, textile printing is carried out by jetting the ink in the form of droplets and causing the ink to attach itself to the cloth in the form of a dot matrix. As a consequence, the following drawbacks arise:
(1) When the same color is printed uniformly, the printed image develops stripes and other irregularities owing to uneven jetting of the ink from each nozzle of the ink-jet head. This invites a decline in picture quality and can lead to a decline in the commercial value of the printed product or even complete loss of commercial value.
(2) In a case where the amount of ink necessary for dying is greater than that jetted from the ink-jet head, defects such as a decline in color density or undyed portions in the gaps between fibers can occur, depending upon the type of cloth.
(3) When a case in which the printing ink is monochromatic and a case in which a inks of a plurality of colors are mixed are compared, it is found that the absolute amount of ink jetted onto the cloth from the head in the former is less, depending upon the color. This can result in defects such as a decline in color density or undyed portions in the gaps between fibers.
(4) In textile printing on cloth, generally the entire area of the cloth is dyed, as a result of which an enormous amount of ink is jetted from the head. This means that the ink-jet head performs a large number of ink jetting operations. Consequently, head lifetime is shortened, many heads must be used and the heads must be replaced a large number of times. The end result is higher running cost and more troublesome maintenance.
Further, if the amount of ink that attaches itself at the proximity of the nozzle jetting ports becomes large in proportion to the amount of ink jetted from the nozzle, a cleaning operation is necessary to remove the attached ink. This results in reduced printing speed overall.
Accordingly, an object of the present invention is to provide a printing method and apparatus of a higher picture quality, in which improvements are made in terms of printing speed, maintenance and running cost.
Another object of the present invention is to provide a printing method and apparatus in which marks that are used for positioning of an image printed in another printing process, are printed using ink having a very low light resistance and the marks are erased by irradiating with light at the end of the printing process, thereby making it possible to perform printing while eliminating effects upon the printing image.
Another object of the present invention is to provide a printing method and apparatus in which marks that are used for positioning of an image printed in another printing process, are printed using ink having a very low heat resistance and the marks are erased by heating at the end of the printing process, thereby making it possible to perform printing while eliminating effects upon the printing image.
A further object of the present invention is to provide a printing method and apparatus, in which a textile printing portion of a uniform single color is printed by a method other than the ink-jet method, thereby improving picture quality, as well as printed matter obtained by using the method and apparatus and a processed article obtained using the printed matter.
A further object of the present invention is to provide a printing method and apparatus through which it is possible to compensate for a decline in printed color density and insufficient dyeing in case of a cloth having a high ink absorbency or when dying is performed using a monochromatic ink, where the absolute amount of ink tends to be insufficient.
Yet another object of the present invention is to provide a printing method and apparatus through which the lifetime of an ink-jet head can be prolonged by lightening the textile-printing load of ink-jet printing.
Still another object of the present invention is to provide a printing method and apparatus through which it is possible to lower running cost and minimize maintenance.
A further object of the present invention is to provide a printing method and apparatus through which the amount of ink jetted from an ink-jet head is reduced to decrease the amount of ink that attaches itself to the vicinity of the jetting ports, thereby making it possible to reduce the number of cleaning operations needed to remove the attaching ink and, as a result, raise the overall printing speed.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.